We thank H. L. Wu (Shanghai Fisheries University, Shanghai, China), Y. H. Xie (Research Institute for Freshwater Fisheries of Liaoning Province, Liaoning, China), C. H. Liu (Southwest Agricultural University, Sichuan, China), S. P. He and H. Z. Liu (Institute of Hydrobiology, Wuhan, China), K. Matsuura (National Science Museum, Tokyo), S. Kimura and S. Matsui (Kyushu University, Fukuoka, Japan), Y. Akai (Tokyo College of Conservation and Civil Engineering, Tokyo), T. Ishinabe (Yokosuka Nature Museum, Kanagawa, Japan) for loan or collection of materials, K. Sakamoto (University Museum, University of Tokyo, Tokyo) for osteological advice, and K. Hosoya (Kinki University, Nara, Japan) for permission to cite of data from his unpublished Ph. D. thesis. This study was partially supported by a Grant-in-Aid for International Scientific Research (Field Research) (no. 07041150) from the Ministry of Education, Science, Sports and Culture, Japan.